Electrical audio signal processing systems and devices – Circuitry combined with specific type microphone or loudspeaker – With electrostatic microphone
Patent
1996-06-03
2000-05-23
Chang, Vivian
Electrical audio signal processing systems and devices
Circuitry combined with specific type microphone or loudspeaker
With electrostatic microphone
341157, 341155, H04R 300
Patent
active
06067363&
ABSTRACT:
According to the exemplary embodiments, a voltage or current-controlled oscillator is controlled in frequency by the signal (i.e., voltage or current) from a microphone. The frequency modulated signal is applied to a direct digital discriminator that produces a digital representation of the instantaneous frequency at the desired speech sampling rate. The digital discriminator may be formed, for example, by applying the oscillator signal to a direct phase digitizing circuit along with a reference frequency and calculating a sequence of instantaneous phases of the oscillator relative to the reference frequency. The phase sequence is then applied to a digital phase locked loop (or otherwise numerically differentiated) to generate a sequence of binary words representative of instantaneous frequency and therefore representative of the speech waveform. Since the low-level speech waveform substantially does not enter the integrated circuit except as a high-level frequency-modulated carrier, the technique is immune to noise caused by high speed random logic circuits such as microprocessors and DSPs operating on the chip.
REFERENCES:
patent: 3533101 (1970-10-01), Lauchner et al.
patent: 4471340 (1984-09-01), Lewis
patent: 4593266 (1986-06-01), Palmer
patent: 4759069 (1988-07-01), Bernstein et al.
patent: 4847903 (1989-07-01), Schotz
patent: 5084669 (1992-01-01), Dent
patent: 5126743 (1992-06-01), Hobbs
patent: 5189420 (1993-02-01), Eddy et al.
patent: 5220275 (1993-06-01), Holmqvist
patent: 5315583 (1994-05-01), Murphy et al.
patent: 5455868 (1995-10-01), Sergent et al.
International Search Report re PCT/US97/09038 Date of completion of search: Nov. 6, 1997.
Chang Vivian
Ericsson Inc.
LandOfFree
Audio A/D convertor using frequency modulation does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Audio A/D convertor using frequency modulation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Audio A/D convertor using frequency modulation will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1842304